The door furniture of many latch sets and knob sets includes a round rosette with a handle or knob extending therefrom. The rosettes are commonly produced with outer diameters of approximately 55 mm and 65 mm. The two different sizes are available as some customers prefer 55 mm rosettes over 65 mm and vice versa for visual or aesthetic reasons.
Many doors are supplied with a 54 mm door furniture hole pre-drilled therein, in order to receive the cylindrical latch bodies of assemblies with 65 mm rosettes. In contrast, an assembly with a 55 mm rosette requires a 35 mm diameter hole, for receiving the latch body, and a pair of smaller, diametrically opposed, holes for receiving the rosette's mounting posts. If an assembly with a 55 mm rosette is used with a door with a 54 mm pre-drilled hole, it can fail by falling into the hole.
As a result of the above, door furniture manufacturers must, disadvantageously, maintain two inventories of componentry able to suit either assemblies with 55 mm or 65 mm rosettes respectively.